368 



THE PHYSICAL GEOGRAPHY OF THE SEA. 



DIAGRAM B. 



have fairly gained the ascendency, and so remain masters of the 

 field until October, when the bi-annual conflict is again com- 

 menced at the north. The vanquished northeast trades now lead 

 off in the attack, and, as the Diagram C shows, the two combat- 

 ants have force enough about the parallel of 15° north to blow 

 during this month 9 days each. The conflict, instead of being 

 "back to back," is now face to face; instead of blowing away 

 from the medial line, they blow toward it; instead of being a 

 place of high, the medial line is now (§ 657) a place of low ba- 

 rometer. By November the northeast monsoon has pushed the 

 place of equal contest as far down as the parallel of 5° north. 



691. Each monsoon, like the trade-winds, blows from a higher 

 The barometric de- ^o a lowcr baromctcr. Taking up the clew from 

 ecent of the monsoons. ^]^-g f^^.^.^ ^^^ rcsorting again to the graphic meth- 

 od for illustration, we may ascertain,. with considerable accurac}^, 

 not only the relative strength of the northeast and southwest mon- 

 soons of the sea, but also the mean height of the barometer in the 

 interior of India during the southwest monsoon, supposing that 

 monsoon to go no farther than the mountain range, which may be 

 taken at a mean to be about the parallel of 30° north. Now, tak- 



